This invention relates to the boring of bolt holes in mating coupling flanges, with particular applicability to the coupling flanges of turbomachinery.
Presently, the line boring of turbine coupling bolt holes take place after a rotor is replaced, or when new coupling bolts are being installed. With rotor replacement, at least one of the coupling halves is new to the coupling assembly, requiring re-boring of the existing bolt holes to the tight tolerances required. The coupling halves are aligned, and joined together while the coupling bolt holes are bored through both coupling flanges simultaneously. In the case of gas and/or steam turbines, the process is carried out during the critical path of the turbine outage.